(a) Field of the Invention
This invention generally relates to a method or system for controlling the grid on an X-ray tube in order to reduce the amount of soft radiation emitted.
(b) Discussion of Known Art
When an X-ray tube is being used for certain applications, the X-ray tube is operated in relatively short bursts at a relatively high frequency in order to obtain clear images. Typically, the tube is operated at approximately 4-6 ms bursts. This relatively small X-ray tube current produced with pulsed fluoroscopy does not sufficiently discharge the capacitance of the high-voltage cables connecting the power supply and X-ray tube between exposure frames. Accordingly, the pulse waves do not have sharp “square” shape, but produce a “tail” of output after the desired peak of the burst has been reached. The “tail” on the power supply output waveform produces unwanted soft radiation that adds to the patient dose and does not improve the image. It would thus be desirable to provide a high-voltage power supply for an X-ray tube that produced substantially rectangular waveforms without a trailing tail of unwanted soft radiation.